Compact steam-fed heat exchange system

ABSTRACT

A compact tank-less self-contained modular hot water supply system is provided for utilizing steam by-products from boiler systems for on-demand supply of temperature-controlled hot water in high volumes suitable for commercial applications. The modular system includes a brazed-plate type heat exchanger with a steam side providing a heating source, and a separate water side for production and delivery of hot water. Precise temperature control is provided by a module that adjusts the temperature of the hot water supply in communication with a module that regulates the flow of steam into the heat exchanger. The modular hot water supply system is contained within a housing which is mountable on a vertical or a horizontal surface.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 60/581,701 filed Jun. 23, 2004 entitled “Compact Steam-Fed Heat Exchange System.”

FIELD OF THE INVENTION

The present invention relates to the field of heat exchange systems, and more particularly, to compact/modular steam-fed heat exchange systems for on-demand high-volume output of controlled-temperature hot water.

BACKGROUND

Commercial dry-cleaning operations have a high demand for hot water. Even a lower-capacity washing machine used in commercial dry-cleaning operations has four washing cycles per load with each cycle requiring at least two gallons of hot water (i.e., at a temperature approximately 65° C.). It is common for each machine to process two loads per hour thereby requiring a supply of sixteen gallons of hot water per hour. However, cosiderable heat is lost during the washing process and therefore, the total hourly hot water requirement for said low-capacity washing machine is double the, volume required for the physical washing process, i.e., a total of 32 gallons per hour (GPH).

A small commercial dry-cleaning operation may have three of these types of low-capacity washing machines thereby requiring a hot water supply of 96 GPH. This translates into an energy requirement of approximately 150,000 British Thermal Units per hour (BTUH). Medium-sized dry-cleaning operations may have five or more such washing machines thereby requiring 160 GPH with a concomitant energy requirement of 250,000 BTUH. These hot water requirements are typically supplied by gas-fired insulated hot water heaters in the 100-gal range which sometimes feed larger storage tanks in the 500-gal. range. Larger plants for commercial laundry or dry-cleaning operations often require 800 to 1,000 GPH. Hot water requirements of this scale are supplied by boiler-generated steam. Furthermore, most commercial laundries and dry-cleaning facilities also require boiler-generated steam for operating presses and other equipment.

SUMMARY OF THE INVENTION

According to one exemplary aspect of the present invention, there is provided a compact tank-less modular heat exchange system for utilizing energy derived from boiler-generated steam for production of an on-demand supply of temperature-controlled hot water. The steam side of the heat exchange system comprises a steam inlet, a steam trap, a steam valve feeding into the inlet side of a plate-type heat exchange unit. The steam side of the heat exchange unit exits into a steam trap feeding a condensate outlet line. The water side (i.e., the fluid side) of the plate-type heat exchange unit is connected to a cold water supply line which is passed through water strainer and check valve modules. The outlet of the fluid side of the heat exchange unit is connected to a dual pressure/temperature valve. The temperature of hot water exiting the fluid side of the heat exchange unit is modulated by a thermocouple connecting the outlet of the fluid side of the heat exchange unit with the steam valve.

According to another exemplary aspect of the present invention, there is provided a heat exchange system for utilizing the energy derived from steam for production of an on-demand supply of temperature controlled hot water. The steam side of the heat exchange system comprises a steam inlet, a steam trap, a steam valve feeding into the inlet side of a plate-type heat exchange unit. The steam side of the heat exchange unit exits into a steam trap and a condensate outlet line. The water side (i.e., the fluid side) of the plate-type heat exchange unit is connected to a cold water supply line which is passed through water strainer and check valve modules. The outlet of the fluid side of the heat exchange unit is connected to a dual pressure/temperature valve. The temperature of hot water exiting the fluid side of the heat exchange unit is modulated by a thermocouple connecting the outlet of the fluid side of the heat exchange unit with the steam valve. The system is also provided with a dual pressure/temperature relief valve to facilitate the on-demand supply and delivery of temperature-controlled hot water.

According to another exemplary aspect of the present invention, there is provided a hot water supply system comprising: a first module having a steam path between a steam inlet and a steam outlet and a water path between a water inlet and a water outlet, the water path being in proximity to the steam path; a second module for supplying a flow of steam to the steam inlet of the steam path of the first module; a third module for receiving the flow of steam from the steam outlet of the steam path in the first module; a fourth module for supplying a cold water supply to the water inlet of the water path of the first module; a fifth module for receiving a hot water supply from the water outlet of the water path of the first module; and a sixth module for controlling the temperature of the hot water supply from the fifth module for delivery.

According to yet another exemplary aspect of the present invention, there is provided a compact tank-less modular heat exchange system for production of an on-demand supply of temperature controlled hot water wherein the system is self-contained within a housing. The housing is mountable on a vertical wall or alternatively, on a horizontal support.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in conjunction with reference to the following drawings in which:

FIG. 1 is a cross-sectional right side view of one embodiment of the present invention;

FIG. 2 is a cross-sectional left side view of the embodiment shown in FIG. 1;

FIG. 3 is a rear view of the embodiment shown in FIG. 2;

FIG. 4 is a cross-sectional left side view of another embodiment of the present invention; and

FIG. 5 is a rear view of the embodiment shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention provides a compact modular steam-fed heat exchange system for supplying an on-demand high-volume output of controlled-temperature hot water without the requirement for storage tanks to hold heated water; The tank-less heat exchange system uses the waste energy given off by boiler-generated steam used in commercial-scale laundry and dry-cleaning equipment such as driers and presses, to heat cold water to useful high temperatures. Embodiments of the present invention provide a wide range of thermal output capacities using a fraction of the space and volumes required by conventional hot water generating systems.

One embodiment of the present invention for a modular steam-fed heat exchange system for providing on-demand high-volume output of temperature controlled hot water is illustrated in FIGS. 1, 2 and 3. The heat exchange system is comprised of a steam side that provides the energy source for heating water, while the fluid side provides the supply of water to be heated to various temperatures on demand.

The steam side is illustrated in FIG. 1 wherein waste steam from a boiler system is introduced through inlet 10 comprising a brass nipple 11. Steam inlet 10 is fitted with a steam pressure relief valve 12 that is connected to nipple 21 by means of a tee coupling 13. A modulating steam valve 14 controls the entry of steam into a heat exchange unit 15. The outlet on the steam side of the heat exchange unit 15 is connected by inline coupling 16 to a steam trap 17. As heat is transferred from steam during its passage through the steam side of heat exchange unit 15, the steam condenses into water which is collected in the steam trap 17 and then removed from the system through the condensate line out 22.

FIG. 2 illustrates the fluid, i.e. water, side of the heat exchange system. Nipple 31 serves as the cold water inlet 30 connected at one end to a water strainer 32, which serves to remove physical particles from water entering the system. Water strainer 32 is connected to a check valve 33 by nipple 41. The water then passes into the heat exchange unit 15 where it is heated by the steam passing through the steam side of the heat exchange unit 15. The heated water leaves the fluid side of the heat exchange unit through nipple 51, which is attached at one end to the heat exchange unit 15 by means of a union 34. The other end of nipple 51 is attached to a tee coupling 35. One end of tee coupling 35 is attached to nipple 61, which is fitted with an elbow (e.g., 90°) 36, which is connected to a nipple 71.

The nipple 71 is connected to the inlet side of a dual pressure/temperature gauge/valve 37. The outlet side of the dual pressure/temperature gauge is fitted with nipple 81 that serves as the hot water outlet 38 for the engineered modular steam-fed heat exchange system of the present invention. If so desired, a cold water supply may be connected to the dual pressure/temperature gauge by means of nipple 91 connected at one end to the water strainer 32 and at the other end to a mixing valve (not shown). A hex-nipple 23 is attached to the third opening of tee coupling 35.

One end of a thermocouple 20 is connected to the hex-nipple 23, while the other end of thermocouple 20 is connected to steam valve 14. Thermocouple 20 modulates the amount of steam allowed to pass through steam valve 14 into the heat exchange unit thereby precisely controlling the heating of cold water passing into the fluid side of the heat exchange unit 15, to a selected temperature.

Another embodiment of the present invention is shown in FIG. 4 wherein the hot water transfer system exiting the fluid side of the heat exchange unit 15 through nipples 51 and 61, is provided with a dual pressure/temperature relief valve 43. Nipple 61 is connected to a tee coupling 42 which at one end is attached to the dual pressure/temperature relief valve 43 and at the other end, is attached to a nipple 121, which is attached to a tee coupling 45. Tee coupling 45 is connected to a dual pressure/temperature gauge 37 by means of a bushing 46. The dual pressure/temperature gauge controls the release of hot water out of the hot water outlet by means of nipple 131. The dual pressure/temperature pressure relief valve makes it possible to deliver a lower temperature of on-demand hot water under constant pressure by providing an outlet 44 for through nipples 91 and 111. If so desired, a cold water supply may be connected to the dual pressure/temperature gauge 37 by means of nipple 91 connected at one end to the water strainer 32 and at the other end to a mixing valve (not shown).

The modular steam-fed heat exchange system according to the various embodiments of the present invention for providing on-demand high-volume output of temperature controlled hot water does not require pre-heating, then storage and maintenance of heated water in insulated tanks. Rather, the various embodiments of the present invention provides a constant on-demand supply of hot water at temperatures that can be controlled by using steam generated by-products from boilers, passing said steam through the steam side of a heat exchange unit, and using the energy derived from the steam to heat a cold water supply passing through the fluid side of the heat exchange unit. The temperature of the hot water produced can be controlled using a thermocouple (for example) cooperating with: (a) a dual pressure/temperature relief valve on the fluid side of a heat exchange unit, and (b) a modulating steam valve on the steam side of the heat exchange unit. Furthermore, embodiments of the present invention do not require the use of electrical controls or connections for its operation.

The various modular heat exchange systems according to embodiments of the present invention discussed above can be housed within a container having, as illustrated in FIGS. 3 and 5, a right side wall 19, a left side wall 37, a back wall 39, along with a top, bottom and front wall (not shown). The heat exchange unit 15 is attached to the right side wall 19 of the container by mounting plate 18. The container can be mounted on a wall or alternatively if so preferred, on a horizontal support (not shown). This results in a relatively compact practical implementation of a heat exchange system. By way of example, modules required for a 250,000 BTUH supply of on-demand hot water (i.e., to supply 250 GPH) can be housed within a steel container with the dimensions of 40 cm wide×50 cm high×20 cm deep (i.e., 16″×20″×8″). In this particular example, a plate-type heat exchange unit comprised of 8 plates can be used. In a second example, modules required for a 1.25 million BTUH supply of on-demand hot water (i.e., to supply 1,200 GPH) can be housed within a steel container with the dimensions of 50 cm wide×50 cm high×20 cm deep (i.e., 20″×20″×8″). In this particular example, a plate-type heat exchange unit comprised of 40 plates can be used.

The present invention is amenable for producing hot water for a variety of commercial applications such as but not limited to, the dry-cleaning industry, laundry facilities for hotels and hospitals, restaurants and the hospitality industries. 

1. A compact tank-less self-contained modular hot water supply system, comprising: a first module comprised of a heat exchanger having a steam path with an inlet connected to a second module and an outlet connected to a third module, a water path with an inlet connected to a fourth module and an outlet connected to a fifth module, the steam path adjacent the water path for transferring heat thereto; the second module configured for receiving a steam supply and controlling a flow of steam therethrough, the third module configured for receiving a flow from the outlet of the steam path; the fourth module comprised of a cold water supply to the water path inlet; the fifth module configured for receiving a hot water supply from the water path outlet; and a sixth module having an inlet, a configuration for monitoring and modulating the pressure and temperature of the hot water supply, and an outlet for delivery of temperature controlled hot water.
 2. A self-contained module hot water supply system according to claim 1 further comprising a housing for containing all of the modules therein.
 3. A self-contained modular hot water supply system according to claim 1 wherein the inlet of the steam path in the first module is positioned opposite the outlet of the water path, and the outlet of the steam path is positioned opposite the inlet of the water path.
 4. A self-contained modular hot water supply system according to claim 3 wherein the first module is a heat exchanger having a plurality of integrally connected steam paths terminating in a common inlet and a common outlet, and a plurality of integrally connected water paths terminating in a common inlet and common outlet, wherein the steam paths are adjacent to and intercalated with the water paths.
 5. A self-contained modular hot water supply system according to claim 4 wherein the first module comprises a brazed-plate type of heat exchanger.
 6. A self-contained modular hot water supply system according to claim 4 wherein the second module is equipped with a steam pressure relief valve.
 7. A self-contained modular hot water supply system according to claim 6 wherein the second module is equipped with a steam modulating valve.
 8. A self-contained modular hot water supply system according to claim 1 wherein the second module is equipped with a steam pressure relief valve and a steam modulating valve.
 9. A self-contained modular hot water supply system according to claim 1 wherein the third module is equipped with a steam trap, the steam trap having an outlet exiting the housing.
 10. A self-contained modular hot water supply system according to claim 1 wherein the fourth module is equipped with a check valve.
 11. A self-contained modular hot water supply system according to claim 1 wherein the fourth module is equipped with a check valve and a water strainer.
 12. A self-contained modular hot water supply system according to claim 1 wherein the fifth module is equipped with a temperature sensing device for communicating therewith the second module.
 13. A self-contained modular hot water supply system according to claim 12 wherein the temperature sensing device is a thermocouple.
 14. A self-contained modular hot water supply system according to claim 1 wherein the sixth module is equipped with a dual pressure and temperature gauge.
 15. A self-contained modular hot water supply system according to claim 1 wherein the sixth module is equipped with a temperature sensing device for communicating therewith the second module.
 16. A self-contained modular hot water supply system according to claim 15 wherein the temperature sensing device is a thermocouple.
 17. A self-contained modular hot water supply system according to claim 2 wherein the housing is comprised of a sheet metal selected from the group consisting of stainless steel, mild steel, aluminium, and galvanized metal.
 18. A self-contained modular hot water supply system according to claim 2 wherein the housing is comprised of a rigid composite material selected from the group consisting of plastics, fibreglass, and synthetic fibres.
 19. A compact tank-less self-contained modular hot water supply system, comprising: a first module comprised of a heat exchanger having a steam path with an inlet connected to a second module and an outlet connected to a third module, a water path with an inlet connected to a fourth module and an outlet connected to a fifth module, the steam path adjacent the water path for transferring heat thereto; the second module configured for receiving a steam supply and controlling a flow of steam therethrough, the third module configured for receiving a flow from the outlet of the steam path; the fourth module comprised of a cold water supply to the water path inlet; the fifth module configured for receiving a hot water supply from the water path outlet; a sixth module configured to monitor and modulate the pressure and temperature of the hot water supply, the sixth module connected to the fifth module; a seventh module having a first inlet connected to the fourth module, a second inlet connected to the sixth module, and an outlet for delivery of temperature-controlled water, the seventh module configured to provide controllable mixing of the cold water supply and the hot water supply; an eighth module configured to provide a pressure and temperature relief system for the hot water supply; and a housing for containing the modules therein.
 20. A hot water supply system comprising: a first module having a steam path between a steam inlet and a steam outlet and a water path between a water inlet and a water outlet, the water path being in proximity to the steam path; a second module for supplying a flow of steam to the steam inlet of the steam path of the first module; a third module for receiving the flow of steam from the steam outlet of the steam path in the first module; a fourth module for supplying a cold water supply to the water inlet of the water path of the first module; a fifth module for receiving a hot water supply from the water outlet of the water path of the first module; and a sixth module for controlling the temperature of the hot water supply from the fifth module for delivery. 